将Python日志器的输出重定向到tkinter组件

Question

我花了一些时间在将输出重定向到tkinter的文本框，并记录输出内容上，现在我需要一些帮助。我的代码如下：

#!/usr/bin/env python
from Tkinter import *
import logging
from threading import Thread

class IODirector(object):
    def __init__(self,text_area):
        self.text_area = text_area

class StdoutDirector(IODirector):
    def write(self,str):
        self.text_area.insert(END,str)
    def flush(self):
        pass

class App(Frame):

    def __init__(self, master):
        self.master = master
        Frame.__init__(self,master,relief=SUNKEN,bd=2)
        self.start()

    def start(self):
        self.master.title("Test")
        self.submit = Button(self.master, text='Run', command=self.do_run, fg="red")
        self.submit.grid(row=1, column=2)
        self.text_area = Text(self.master,height=2.5,width=30,bg='light cyan')
        self.text_area.grid(row=1,column=1)

    def do_run(self):
        t = Thread(target=print_stuff)
        sys.stdout = StdoutDirector(self.text_area)
        t.start()

def print_stuff():
    logger = logging.getLogger('print_stuff')
    logger.info('This will not show')
    print 'This will show'
    print_some_other_stuff()

def print_some_other_stuff():
    logger = logging.getLogger('print_some_other_stuff')
    logger.info('This will also not show')
    print 'This will also show'

def main():    
    logger = logging.getLogger('main')
    root = Tk()
    app = App(root)
    root.mainloop() 

if __name__=='__main__':
    main()

我知道可以根据文本框定义一个新的日志处理器，但我一直搞不定。这个“print_stuff”函数其实只是一个包装器，里面调用了很多不同的函数，每个函数都有自己的日志记录器。我需要帮助来定义一个新的“全局”日志处理器，这样每个有自己日志记录器的函数都可以使用它。非常感谢任何帮助。

Answer 1

这是一个完全修订过的答案，可以满足你的需求。我尽量标明了你问题中的代码哪些行被修改了，哪些行是新加的。

默认情况下，内置的logger.StreamHandler类会把信息输出到sys.stderr，所以如果你想把这些信息也重定向到sys.stdout，就需要创建一个新的日志记录器，并设置一个自定义的控制台处理器来实现这个功能。因为你希望这个设置适用于模块中的所有日志记录器，所以需要对没有名字的“根”日志记录器进行设置，其他有名字的日志记录器都会从这个根日志记录器继承设置。

from Tkinter import *
import logging
from threading import Thread

class IODirector(object):
    def __init__(self, text_area):
        self.text_area = text_area

class StdoutDirector(IODirector):
    def write(self, msg):
        self.text_area.insert(END, msg)
    def flush(self):
        pass

class App(Frame):
    def __init__(self, master):
        self.master = master
        Frame.__init__(self, master, relief=SUNKEN, bd=2)
        self.start()

    def start(self):
        self.master.title("Test")
        self.submit = Button(self.master, text='Run', command=self.do_run, fg="red")
        self.submit.grid(row=1, column=2)
        self.text_area = Text(self.master, height=2.5, width=30, bg='light cyan')
        self.text_area.grid(row=1, column=1)

    def do_run(self):
        t = Thread(target=print_stuff)
        sys.stdout = StdoutDirector(self.text_area)
        # configure the nameless "root" logger to also write           # added
        # to the redirected sys.stdout                                 # added
        logger = logging.getLogger()                                   # added
        console = logging.StreamHandler(stream=sys.stdout)             # added
        logger.addHandler(console)                                     # added
        t.start()

def print_stuff():
    logger = logging.getLogger('print_stuff') # will inherit "root" logger settings
    logger.info('This will now show')                                  # changed
    print 'This will show'
    print_some_other_stuff()

def print_some_other_stuff():
    logger = logging.getLogger('print_some_other_stuff') # will inherit "root" logger settings
    logger.info('This will also now show')                             # changed
    print 'This will also show'

def main():
    logging.basicConfig(level=logging.INFO) # enable logging           # added
    root = Tk()
    app = App(root)
    root.mainloop()

if __name__=='__main__':
    main()

Answer 2

我想确认一下我理解得对不对：

你想把日志信息同时打印到标准输出（STDout）和Tkinter的文本框里，但日志却不在标准控制台显示。

如果这确实是你遇到的问题，下面是解决方法。

首先，我们来创建一个非常简单的Tkinter控制台，实际上可以用任何文本框，但我这里还是加上以便完整：

class LogDisplay(tk.LabelFrame):
"""A simple 'console' to place at the bottom of a Tkinter window """
    def __init__(self, root, **options):
        tk.LabelFrame.__init__(self, root, **options);

        "Console Text space"
        self.console = tk.Text(self, height=10)
        self.console.pack(fill=tk.BOTH)

接下来，我们要修改日志处理器，让它能把信息发送到指定的控制台，同时还能自动打印到标准输出：

class LoggingToGUI(logging.Handler):
""" Used to redirect logging output to the widget passed in parameters """
    def __init__(self, console):
        logging.Handler.__init__(self)

        self.console = console #Any text widget, you can use the class above or not

    def emit(self, message): # Overwrites the default handler's emit method
        formattedMessage = self.format(message)  #You can change the format here

        # Disabling states so no user can write in it
        self.console.configure(state=tk.NORMAL)
        self.console.insert(tk.END, formattedMessage) #Inserting the logger message in the widget
        self.console.configure(state=tk.DISABLED)
        self.console.see(tk.END)
        print(message) #You can just print to STDout in your overriden emit no need for black magic

希望这能帮到你。